Knierim, IN;
(2008)
Orthographic influence on speech processing: A combined TMS and behavioural study.
Doctoral thesis , UCL (University College London).
Preview |
Text
Knierim_thesis.pdf Download (9MB) | Preview |
Abstract
Previous behavioural studies of auditory lexical decision have shown longer reaction times due to inconsistent spelling of a word's rime - the sound after the first consonant cluster (e.g.,-ight/-ite) - when compared to consistently spelt rimes (e.g.- ust). A possible explanation is that co-activation of orthographic representations during word processing is triggering the effect. An alternative account assumes that the process of learning to read and write contributed to the restructuring of phonological representations, such that inconsistent rimes induce competition of competing phonological representations reflected by longer reaction times. To test these hypotheses, we applied repetitive transcranial stimulation (rTMS) to the left supramarginal gyrus (SMG), to the left posterior fusiform gyrus (FUS) and two control sites. Two experiments (n=47) were conducted applying rTMS (400ms of 10Hz at 100% motor threshold) to either SMG, FUS or a respective control site. A control task using auditory semantic categorisation was tested at the same site. ANOVA 2(Stimulation) x 2(Site) x 2(Consistency) run on the lexical decision reaction time data of the first experiment showed a three-way interaction F(l,16) = 7.2, p < .05: the orthographic effect disappeared only when the stimulation was applied on SMG. No TMS effect was found in the control task regardless of the site of stimulation (Fs < 1). Considering the SMG involvement in phonological processing, the data suggests that the consistency effect is mediated at a phonological level presumably because learning to read fundamentally reshapes phonological representations. TMS to SMG disrupts the processing advantage for consistent words by adding noise to performed computation, while TMS to FUS does not affect the consistency effect.
| Type: | Thesis (Doctoral) |
|---|---|
| Title: | Orthographic influence on speech processing: A combined TMS and behavioural study |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Thesis digitised by ProQuest. |
| UCL classification: | UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1569597 |
Archive Staff Only
 |
View Item |
